The four Sinn Féin MPs who have yet to take up their seats at Westminster each claimed more than £100,000 in parliamentary expenses and allowances last year.
Ulster Unionist Party leader Mr David Trimble claimed just over £70,000.
Fermanagh and South Tyrone Sinn Féin MP Michelle Gildernew topped the Sinn Féin list, claiming £115,420 in expenses and allowances between April 2003 and March 2004.
That sum included £18,400 in so-called Additional Costs Allowance, paid "to reimburse Members for necessary costs incurred when staying overnight away from their main home for the purpose of performing parliamentary duties".
Ms Gildernew also claimed £67,738 in staff costs.
Sinn Féin president Gerry Adams, MP for West Belfast, claimed £109,315 in expenses and allowances in the same period, including £18,268 in ACA and £64,263 in staff costs.
Sinn Féin chief negotiator Martin McGuinness, MP for Mid Ulster, claimed £110,653, including £18,581 in ACA and £64,272 in staff costs.
West Tyrone MP Pat Doherty claimed a total of £104,064, including £18,320 ACA and £60,982 staff costs.
Mr Trimble claimed £71,134, including £18,009 ACA and 339,119 staff costs.
Sinn Féin MPs have office accommodation at Westminster but have not sworn or affirmed the oath of allegiance to the Queen and taken their seats.
Nobody from the party was immediately available to comment.
PA