The Liberal Democrats should introduce quotas to boost gender and ethnic diversity if the party continues to be "unrepresentative" of Britain, according to Nick Clegg.

The deputy leader, speaking at a Mumsnet question and answer session, revealed that greater female and ethnic minority representation "matters massively" to him.

The Liberal Democrat leader also explained that his party had implemented measures to boost diversity, but he would support the introduction of quotas if the situation does not improve.

"Our dilemma is that we don't have many safe seats; we have to work very hard to win seats," Clegg said.

"We're making sure that MPs standing down are being replaced by women and/or black, Asian or ethnic minority candidates where possible.

"We've got a support and mentoring programme for those candidates. If that doesn't work and it continues to be this unrepresentative after the election, I personally think we should introduce quotas.

"That's my personal view – it may feel uncomfortable for some people in our party."

The comments come after a report from think-tank British Future found that the number of ethnic minority MPs is set to hit a record high after the general election.

The organisation's analysis found that the number of representatives from ethnic minority backgrounds will rise to 44 following May's hotly contested vote.

The Liberal Democrats currently have 56 MPs in the House of Commons but none are from black, Asian or ethnic minority backgrounds.

Clegg also expressed his concern about some aspects of the government's social security system during the question and answer session.

Welfare sanctions

He claimed that the Department for Work and Pension's sanctions (when a benefit is suspended or removed from a claimant) were too "trigger-happy".

"I'm uncomfortable about welfare sanctions though – I think they're a bit too trigger-happy. The guillotine comes down too quickly," Clegg argued.

"It's fair enough to attach strings to benefits payments, but we need to look at how effective they are – we're looking at a possible traffic light/yellow card system that might provide considerable help to people who get caught out by the rapid imposition of sanctions."

The deputy prime minister, who admitted he did not know whether it was a "traffic light" or "yellow card system", explained that the reform would see benefit recipients being issued with a warning before a sanction.

The comments come with just weeks to go before the general election, with the Liberal Democrats well behind their 22% share of the vote in 2010.

The latest poll from YouGov put Clegg's party on 8%, just ahead of the Greens on 8% and behind Ukip on 12%.

The study, which surveyed more than 2,000 voters between 23 and 24 March, also found that Labour and the Tories were level-pegging at 35% each.