Hungary receives between five and eight billion cubic metres of Russian gas a year through the TurkStream pipeline, which both Hungary and Slovakia depend on for Russian gas.
Balint Pasztor, president of the Vojvodina Hungarian Association, and another key Orban ally, posted on Facebook: "If the investigation proves that we were not the primary target after all, but rather Hungary's supply lines, then this makes it even clearer: the terrorist attack was planned with the aim of bringing down Viktor Orban."
Fidesz has made hostility to Ukraine a cornerstone of its election campaign.
At election rallies Orban has told supporters that low heating and fuel prices in Hungary are only possible thanks to cheap Russian oil and gas, both of which arrive in Hungary by pipeline - oil through Ukraine, and gas through the Balkans.
Orban alleges that a "Kyiv-Brussels-Berlin" axis is conspiring to stop Hungary getting cheap Russian fuel, to impose their "puppet" prime minister Magyar in the upcoming election. A Tisza government, Orban says, would also drag Hungary into a European war against Russia.
Orban has already accused Ukrainian president Volodymyr Zelensky of imposing "an oil blockade" on Hungary, because no Russian oil has arrived through the Druzhba pipeline, which crosses Ukrainian territory, since the end of January.
Ukraine says the pipeline was damaged in a Russian attack, and should be functional again in-mid April.
There have been no official allegations of Ukrainian involvement in the pipeline incident so far. But one well-informed Serbian source told the BBC this could happen as early as Monday, when Serbian authorities are expected to release the first results of their investigation.
The Ukrainian government pre-empted any accusations of involvement on Sunday. "Ukraine has nothing to do with this," foreign ministry spokesman Heorhiy Tykhyy said in a post on X. "Most probably, a Russian false-flag operation as part of Moscow's heavy interference in Hungarian elections."
On 2 April, Hungarian security expert Andras Racz warned on Facebook that a "fake attack" on the TurkStream pipeline could be staged inside Serbia.
Racz also predicted that the explosives would be identified as Ukrainian, allowing Orban to once again point the finger of blame at Kyiv.
"We had some solid preliminary information about this operation, including details about the place and possible timing," former senior Hungarian counter-intelligence officer, Peter Buda, told the BBC.
"It's clear that Ukraine's interests aren't at stake here. An operation like this would help Orban before the election by influencing public opinion in his favour.''
The Hungarian government insists the threat is real. "In the past few days and weeks, we've seen it all," Hungarian Foreign Minister Peter Szijjarto wrote on Facebook.
"The Ukrainians organised an oil blockade against us. Then they tried to impose a total energy blockade on us by firing dozens of drones at the TurkStream pipeline while it was still on Russian territory.
"And now we have today's incident, in which Serbian colleagues found explosives capable of blowing up the pipeline."
Opposition leader Peter Magyar accused Orban, in cahoots with the Serbian president, of staging the latest incident.
"He will not be able to prevent next Sunday's election. He will not be able to prevent millions of Hungarians from ending the most corrupt two decades in our country's history."