New calculations from the Tenants Union of Victoria show the single Newstart allowance with rent assistance now either just meets or fails to meet the median rent in every capital city other than Adelaide and Hobart.

Newstart is $244.85 a week, rent assistance an extra $60.10. In Melbourne the $304.95 total barely meets the $300 median rent on a one-bedroom flat. In Sydney it falls well short of the $420 per week needed.

If a job seeker on Newstart decides to share, paying half the rent on a two-bedroom flat, rent assistance is cut, bringing it down to $284.90 a week, leaving just $109.90 to spare after rent of $175. The excess needed for food, clothes, fares and utility bills works out at $15.70 per day.

Tenants Union of Victoria liaison officer Toby Archer says single Australians looking for work have to adapt, renting housing below the median, sharing overcrowded houses, couch surfing and using boarding houses and caravan parks.

''But even in boarding houses rent consumes a big part of their income. They spend as little as they possibly can on food, they avoid going to the doctor or the dentist, they don't buy medication. They find it hard to present themselves for jobs. By the time we see them they are behind on their rent, they've already eaten into savings, sold their cars and pawned things of value.''

Once comparable to the pension, Newstart has failed to keep pace since the two were indexed separately in 1997. The unemployment benefit is now two-thirds of the single pension and slipping with each half-yearly adjustment. In March the pension was lifted $3.35 a week, Newstart $1.45 a week.

Greens leader Christine Milne this week committed herself to winding back some of the $132.90 a week gap, saying some of the planned cut in company tax should be diverted to lifting Newstart $50 a week.

Treasurer Wayne Swan has told the Press Club in the lead-up to the budget there is ''a case about the gap that has opened up'', but adding, ''how we can deal with that in the longer term is a difficult one given the fiscal pressures and so on the government is facing''.

Greens senator Rachel Siewert is this week attempting to live on $17 a day, her calculation of what Newstart job seekers have if they handed over only half their income in rent.