Smith's spokesman, Steve Miskin, replied that as Smith's attorneys interpret the law, the speaker cannot move to fill the seats until a new set of boundaries for House districts has been approved by the court - a prospect that is months away.
The House is currently populated by 110 Republicans and 87 Democrats. At least four of the six vacant seats would likely be filled by Democrats.
All six of the vacancies occurred when House members resigned to take local political offices they had won in the November election.
Three of the empty seats are in Philadelphia - formerly held by the new sheriff, Jewell Williams, and two City Council members, Dennis O'Brien and Kenyatta Johnson. A fourth is in Montgomery County - the seat Shapiro gave up to become a county commissioner.
Nutter and his colleagues cited three reasons for a rapid decision to hold the special elections on the same date as the primary, April 24: the extra expense of conducting a special election on another date, the legal requirement for 60 days' notice before special elections could be held, and the fact that as many as 250,000 constituents are without representation in the House.
"Our constituents deserve, and our counties need, full representation in Harrisburg, especially during these difficult budget times," their letter said. "It is simply not right to have some citizens fully represented while others are not."
Smith's inclination is, to avoid public confusion, to wait until new legislative borders are set by a Legislative Redistricting Commission and approved by the state Supreme Court, Miskin said.
The high court rejected the commission's first redistricting proposal last month. A new plan is expected to be unveiled next week, but it will be late April, at the earliest, before the Supreme Court rules on it.
Until new maps are approved, the old district lines, established in 2001, remain in effect.
Miskin said Smith thinks those boundaries are constitutionally suspect because of wide variations in population. A coalition of Hispanic organizations says the old lines deprive Latino voters of political power they should have achieved through population growth.
If a special election were held in conjunction with the April 24 primary, Democratic and Republican ward leaders would pick candidates to represent the respective parties, and voters would choose among them for someone to fill the seats for the remainder of 2012.
On the same voting machines, voters would have a choice of candidates seeking party nominations to fill the seats for the next legislative session, starting in January 2013. But the possibility of new legislative boundaries leaves the situation unsettled, still to be decided by the legislature and the courts.
In related activity, state election officials said Friday that three candidates seeking House seats from Philadelphia had been omitted from a list of candidates posted the night before, after the deadline for candidates to submit nominating petitions.
The three candidates are: Republican Al Taubenberger, filing to run against incumbent Rep. Kevin Boyle, a Democrat; Democrat Paul Hagins, joining the Center City race against incumbent Babette Josephs and Brian Sims; and Fareeda Mabry, a Democrat from Darby Borough, joining the race against incumbent Maria Donatucci and challenger Norma McNeil. Donatucci's district includes parts of Philadelphia and Delaware Counties.
Contact staff writer Bob Warner at 215-854-5885 or firstname.lastname@example.org.
Inquirer staff writer Angela Couloumbis contributed to this article.