The corporate deemed the potential crash to be a "very excessive threat".
Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said the two objects were Soviet navigation satellites called Paras. The other orbiting object is the upper-stage rocket body from a Chinese launch in 2009.
In a tweet it said there was a greater than 10 per cent chance of the objects colliding, after warning of a 1 to 20 per cent chance of a collision on Thursday. The satellite is a Russian Parus military satellite launched on February 22, 1989.
The combined mass of the two objects, which would impact each other with a relative velocity of 14.7 km/s, is approximately 2,800 kg.
It wouldn't be the first time that two large pieces of space junk have collided. Our system generates new conjunction reports 6-8x per day on this event with new observation data each time.
LeoLabs said that the Chinese rocket body was scheduled to pass directly over its Naseby space junk radar soon after the possible collision.
LeoLabs will track junk space tonight to see if it collides.
In 2009, a communications satellite collided with an invalid Russian satellite, resulting in 1,800 pieces of debris.
It would use the radar to check whether debris had been created.
"As of January 2019, there's more than 128 million pieces of debris smaller than 1/2" about 900,000 pieces of debris less than 4" and around 34,000 of pieces larger than 4" were estimated to be in orbit around the Earth.
The concern over an increase in large collisions relates to the potential of triggering the Kessler Syndrome, where access to space becomes increasingly hard as more and more junk clutters orbit.
While there is over 2,600 active satellites now orbiting Earth, there are also 3,000 dead ones out there.
According to LeoLabs, and as of publication at 3pm EDT, the predicted miss distance for Cosmos 2004 and CZ-4C R/B is just 25 meters (+/-18 meters).
On Wednesday, Rocket Lab spokeswoman Morgan Bailey said that given the size, speed and proximity of the objects being monitored by LeoLabs "everybody in the space industry will be watching it closely with concern".