The Liberal Democrats said ending pay cuts for public sector workers would be a "red line" in any coalition talks.
The Conservatives said they aim to "keep more money in people's pockets" and Labour said voters on the doorstep have been calling for a "fair deal".
Plaid Cymru leader Leanne Wood said Westminster "cannot go back to business as usual" on 8 May after the elections.
On Sunday, the party is focusing on the constitution with a call for voting reform and it also wants to see a new "UK council of ministers" established to discuss UK-wide policy.
The Lib Dems have already proposed that pay for teachers, police and other public sector staff should rise in real terms for two years from 2016, and then by more than inflation once the deficit has been dealt with.
Welsh Liberal Democrat candidate Roger Williams said the policy is a "major commitment that will benefit thousands of people in Wales".
The Conservatives are focusing on personal finances on Sunday, saying the coalition government's changes to the tax system have benefited more than a million people in Wales.
Conservative Wales Office minister Alun Cairns said that "only Conservatives in government can deliver for Wales".
For Labour, Shadow Welsh Secretary Owen Smith said the election is "a choice about the sort of country we want" and that Labour will make a "better Britain and a fairer Wales".
He said he has visited every seat in Wales during this campaign and his conclusion was that people wanted a "fair deal".
On Sunday, UKIP's Nathan Gill told the Sunday Politics Wales programme: "We really do believe that the people who make our laws are the people that are in Westminster or the Welsh Assembly, not in Brussels."
Wales Green party leader Pippa Bartolotti told the programme: "We have a very real and immediate problem with the state of gender pay. I want to help women out of this terrible rut that government after government has kicked them into."
The main political parties in Wales are back on the campaign trail with four days to go to the general election.