An unsigned pamphlet has been circulated in Dili complaining of official discrimination against Timorese from the impoverished country's western region in favour of those from the east.
The pamphlet also threatened protests against the government if an easterner is appointed the new police commander when the post becomes vacant in November.
Such claims of regional discrimination sparked a mass desertion by members of the armed forces, leading to fighting in 2006 between military, police factions and gangs in street violence that killed at least 37 people.
With international troops still patrolling the streets in the wake of that violence that also forced thousands to flee their homes, rumours of a return to instability have caused jitters among some Timorese in the capital.
"I heard about the pamphlet and I'm worried that if (a protest by police against the government) happens than it's going to be worse than 2006," said a police officer, who resigned in the lead-up to trouble two years ago.
The opposition Fretilin party has also announced plans for a large protest against Prime Minister Xanana Gusmao, over his long-standing claim that the formation of his coalition government in 2007 was against the constitution.
Opposition leader Mari Alkatiri has promised thousands of protesters will turn out, but has not yet set a date for the march.
The government has responded to both threats by stepping-up roadblocks in the capital and enforcing a ban on off-duty police officers taking their guns home with them.
President Jose Ramos-Horta, who survived an assassination attempt by rebel soldiers earlier this year, said he would not accept such a protest aimed at "criticising the legitimacy of the government".
Gusmao has discounted the likelihood of unrest but has also urged police to avoid politicking.
"The national police force must display a good attitude so they will be respected. Police officers must show that they are not just carrying out a job, but are willing to serve their country," the premier told AFP.
But deputy police commander Mateus Fernandes denied the pamphlet came from within police ranks, saying unnamed politicians were manufacturing the crisis for political gain.
"This pamphlet is like a dog barking so just let it be and it will quiet down by itself. Some politicians have launched this to realise their own interests via the police and have been using this issue of who will become the police commander," he said.
Edward Rees, a Dili-based analyst and former United Nations security adviser, said the tensions in the police force were not an immediate threat.
But he warned they would likely lay the groundwork for violence "within 12 to 24 months" of the departure of the roughly 2,500 international soldiers and police stabilising the country.
Rees said the pamphlet was part of a bitter internal power struggle in the police with strong parallels to similar tensions in 2004, which in turn helped lay the basis for the 2006 crisis.
"If this kind of agitation was going on in the absence of the 2,500 international soldiers and police that are here then you would have a problem."
A mass rally by Fretilin would be highly destablising but opposition leader Alkatiri is unlikely to carry through with his threat, Rees said.
Fretilin politicians and their backers are making too much money from government contracts to jeopardise that by staging a rally which is expensive to organise and could see contracts dry up, he added.
East Timor Law Journal - Towards the rule of law in Timor-Leste.