With a little more than a month to go before the federal election, a new poll shows the Liberal lead on P.E.I. may be slipping.

According to the poll, Liberal support fell to 38 from 45 per cent, while support for the Conservatives and NDP was the in the 20s.

"I think what stands out in the last three months is that there has been a narrowing of the lead that the Liberals had over the NDP," said Don Mills, Corporate Research Associates's chairman and CEO.

"There was almost a 19-point lead and that's now down to nine points. But the Liberals still obviously have a reasonably comfortable lead. They're still basically in the driver's seat at the moment. But that gap continues to narrow and there are more than four weeks left in the campaign."

The poll of Islanders by CRA, conducted in August, reached 300 Islanders, providing a margin of error of 5.6 percentage points. The margin of error among decided voters is 6.4 percentage points.

Given the margin of error, the drop in support for the Liberals in comparison to a poll conducted in May is statistically significant.

The popularity race between the four leaders appears to be even closer than the race between the four parties, the poll indicated. No leader polled above 25 per cent, and none below 11 per cent. Justin Trudeau's support fell to 25 per cent from 35, putting him squarely in a tie with Thomas Mulcair.

If the poll holds true, P.E.I. could be in for some unprecedented change in 2015.

Since 1988, the Liberal Party has dominated federal politics. It held all four seats from 1988 to 2008. Gail Shea took Egmont for the Conservatives in 2008 and 2011, while Liberals held the other three seats.

Electoral trends since the 2004 election suggested the Tories were on track to finally win back a seat in 2015.

In 2011, the Conservatives actually drew a few hundred more votes than the Liberals Island-wide. Each party took just over 41 per cent of the vote.

The CRA poll, and the dramatic change in voting trends seen in the provincial election earlier this year, suggest Islanders are seriously considering sending someone who is not a Liberal or a Conservative to Parliament.

In the spring provincial election, Islanders elected a Green MLA for the first time. Support for the Greens in the latest poll is double what it is in the rest of Atlantic Canada.

While the Conservatives seemed to be moving slowly back into Islanders' favour over the last four federal elections, this poll suggests that support has now been lost.