Sky News has obtained a copy of the draft report written by the panel tasked with creating a new, independent complaints system to root out abuse in Parliament.
It follows a string of allegations which led to the departures of two Cabinet ministers. Several Conservative and Labour MPs are still under investigation.
A cross-party group, chaired by Leader of the House Andrea Leadsom, took evidence from experts for six weeks, but has yet to publish its proposals.
Mrs Leadsom told the House of Commons in December: "We should not rest until everyone working in Parliament can feel safe, valued and respected".
But the leaked draft concedes that tackling inappropriate behaviour will require a "range of sanctions", but in the short term these will be restricted to measures such as an apology or sending an MP for training.
It reveals that while the group "believes that a change in workplace culture is both urgent and essential", this is a "long-term project beyond the working group's terms of reference."
Unless new legislation is passed, any decision to suspend an MP or peer remains in the hands of political parties, unless they have been jailed for a criminal offence.
Sarah Green, co-director of the End Violence Against Women Coalition, who gave evidence to the MPs, welcomed their aims but feared progress would not be made this year.
She said: "It's kicking a lot of the details into the long grass.
"After a couple of months now of really serious allegations in Westminster and beyond, it's still saying we need to take months longer to decide exactly what the process should be.
"It's also not clear that the decision-making power about who did what to whom, and why it matters, is being removed from the political parties and that's what we actually need... I think we could have got further than this."
A source familiar with the proceedings said: "We need a system that is clearly independent and has teeth, and we haven't got either of those things. It feels like delaying until this blows over."
Interim measures proposed in the report include an online learning module for politicians to ensure "better understanding of bullying and harassment" and a human resources service for Parliament - where MPs are responsible for hiring their own staff.
Other measures it recommends the House of Commons authorities should procure at the earliest opportunity, but for which there is no firm timescale, include:
:: A specialist helpline staffed by qualified experts in sexual harassment - which would be separate from other workplace issues
:: The appointment of a specialist investigator, likely to be a lawyer with experience in this field, to look into allegations independently
:: Another committee to consult on imposing tougher sanctions, and how measures could extend beyond Parliament for example to people MPs encounter in their constituency
Labour MP Jess Phillips, who has campaigned for victims of sexual harassment said: "I totally understand why people would be disappointed.
"For the people who have come forward and spoken up at the moment, it still seems like the Establishment protects the perpetrators.
"This is a draft report and I hope that when it is finally agreed by all parties, that it will be much firmer on exactly what the sanctions are and it will take away any power a political party has to basically cover things up."
Ava Etemadzadeh, a student in her 20s who made allegations of harassment against the MP Kelvin Hopkins - which he denies - said victims could only have faith in a procedure fully independent of political parties. Her claims are under investigation.
She said: "For years we have seen how political parties have failed to handle these cases very well... I know numerous women who still wouldn't want to come forward to talk about it."
In a statement to Sky News, Ms Leadsom said: "This is a very serious matter that the working group are determined to get right, and as the chair, I will not comment on the content of leaked documents.
"We all recognise the need to change the culture in Westminster.
"The Working Group will meet as soon as Parliament returns to make further progress in creating an independent complaints procedure. In the meantime, interim support has been put in place by the House Authorities."
A source close to the Cabinet minister said it was hoped that a tougher system fully independent of the political parties could be agreed in "the early part of this year".
The aim is understood to be for the specialist investigator to work for a beefed-up office of the Parliamentary Standards Commissioner which would have more powers.
Labour's shadow leader of the commons Valerie Vaz sits on the working group and it is claimed that her party vetoed plans to publish this report last year. She could not be reached for comment.